The subject matter disclosed herein relates to a device for filtering a gas and in particular to a device that removes trace contaminants from a gas stream in a pressurized and vacuum environment.
Vehicles such as high altitude, suborbital or spacecraft vehicles utilize air filtration systems to recycle air for use by the vehicles occupants. Typically, the filtration is accomplished using a catalytic reaction of contaminants in one device and an absorption reaction in second device. Each device uses a container that holds media particles. These devices may be arranged in parallel with a single air flow being split into two air streams. Each device has an air flow operating parameter under which it operates to remove the desired contamination. In a typical filtration system, one device processes a larger volume of air than the other device. Since the separate air streams are recombined before being returned for use within the vehicle, additional hardware and components are utilized to equalize the pressure drop of the air streams as they flow through the filtration devices.
These filtration systems operate in a demanding environment that varies from atmospheric pressure to the vacuum of space. A typical filtration system media is not intended to be used in a vacuum environment. Therefore the filtration devices are arranged within vessels with increased wall thicknesses that add weight to the vehicle. Further, the media may be regularly replaced during maintenance operations so the vessels will have joints that need to be sealed. Due to the increased potential for a leakage of one of these seals, spacecraft usually transport additional make up gas that may be used to compensate for any leakage. It should be appreciated that the need for bringing make up gas increases the weight of the air filtration system and decreases available space for payload.
Accordingly, while existing vehicle air filtration systems are suitable for their intended purposes the need for improvement remains, particularly in providing a filtration device that reduces the complexity of installation and also the size and weight of the air filtration system.